Back injection molding processes are known in the cosmetic art. Typically, a cosmetic slurry or other flowable base is injected through a hole in the back, or bottom (which may be oriented upwards), of a plastic (or other type) pan structure to form a finished cosmetic product. Alternatively, a cosmetic base can be metered into a pan through its open top. For purposes of this invention, the terms "back injection molding" and "injecting" shall include all of the foregoing, and shall not be limited by the orientation of the pan, the location of the aperture for accepting the cosmetic base, or the force or specific method used to add the cosmetic base to the pan. Moreover, pans can be made of other materials, such as metal, and can have a variety of shapes, such as square, oval or free-form.
Pans are known and marketed that have permanent partitions forming more than one compartment. Different colors or different products can be injection molded or otherwise deposited into the separate compartments to form a multi-phase product. However, it is desirable to have multi-phase products that do not require a permanent internal partition in the pan. Such internal partitions can increase the cost of the pans, and are less aesthetically appealing, particularly when the product is worn away from the partition as it is used up. Moreover, such structures often require double processing and/or blotting of each pan. Packed, compressed multi-phase powder cosmetics are known that include two or more colors or types of compacted cosmetics in direct contact within a single pan.
However, slurried back-injected cosmetics have not been formed in this manner, nor have other cosmetics that are not compacted powders. Accordingly, a need exists for pan structures and molding methods that can be used to form multi-phase cosmetics with back-injection molding techniques and other non-compaction methods.
Similarly, pressed powders are known that have multi-phase surfaces, such as those having decorative embossments or raised areas. However, a need exists for a method to produce such multi-phase surfaces in slurried cosmetic cakes and other non-compacted products.